A reel of tape valued at £1M
I had to look after a reel of tape, containing a "completed" software application, purported to be worth £1M. The system was never implemented and as far as I know the tape contained nothing more than odd "pieces" of source code. The software formed part of a larger sale and lease back of hardware and software.
The system became material in a later court case, which became famous long after my employment.
https://publications.parliament.uk/pa/ld200001/ldjudgmt/jd010118/intern-1.htm
That reel of tape - well - it's now in Spain.
AC, because they never called me to give evidence, but probably should have.